1. Field of the Invention
The present invention relates to a hard disk drive, and more particularly, to a disk clamp of a hard disk drive having an improved structure to prevent a slip of a disk and damage of a spindle motor from an external impact.
2. Description of the Related Art
A hard disk drive (HDD) is one of the auxiliary memory devices of a computer, which reads out data stored in a magnetic disk or records data on the magnetic disk by using a magnetic head.
FIG. 1 is an exploded perspective view of a conventional hard disk drive. FIG. 2 is an enlarged perspective view of a disk clamp portion of the hard disk drive of FIG. 1. FIG. 3 is a sectional view taken along line C—C, which shows a state in which the disk clamp of FIG. 2 is coupled to the spindle motor.
Referring to FIGS. 1 and 2, a hard disk drive includes a housing 10, a spindle motor 30 installed in the housing 10 to rotate a magnetic disk (a hard disk) 20, and an actuator 40 having a magnetic head 41 for recording and reproducing data on and from the disk 20.
The housing 10 is installed inside a main body of a computer and includes a base plate 11 for supporting the spindle motor 30, the actuator 40 and a cover plate 12 coupled to the base plate 11 for protecting the disk 20 by enclosing the disk 20. The housing 10 is typically manufactured using a stainless steel or aluminum material. The spindle motor 30 is installed on the base plate 11 to rotate the disk 20.
The disk 20 is a recording medium for recording data. A single or plurality of magnetic disks are installed, being separated a predetermined distance from each other and rotatable by the spindle motor 30. A parking zone 21 is located at the inner circumferential side of the disk 20 so that a slider 42, on which the magnetic head 41 is mounted, is accommodated in the parking zone 21 when the power is turned off. A data zone 22, where magnetic signals are recorded, is provided outside the parking zone 21. When a plurality of disks 20 are installed at the spindle motor 30, a ring type spacer 50 is inserted between the disks 20 to maintain a gap between the disks 20. A magnetic disk clamp 60 is coupled to the upper end portion of the spindle motor 30 by a plurality of screws 70 to firmly fix the disk 20 to the spindle motor 30.
The actuator 40 is installed to pivot by a voice coil motor 48 around a pivot shaft 47, installed on the base plate 10. The actuator 40 includes an arm 46, coupled to the pivot shaft 47, to pivot and a suspension 44, installed at the arm 46, to support the slider 42 on which the magnetic head 41 is mounted, and to be biased elastically toward the surface of the disk 20.
In the conventional hard magnetic disk drive having the above structure, when the power is turned off, the slider 42 is accommodated in the parking zone 21 of the disk 20 by an elastic force of the suspension 44. When the disk 20 begins to rotate as the power is turned on, lift by air pressure is generated, and the slider 42 is lifted. The slider 42 in a lifted state is moved to the data zone 22 of the disk 20 as the arm 46 of the actuator 40 pivots. When the slider 42 is moved to the data zone 22 of the disk 20 and maintains a lifted state at a height at which the lift by the rotation of the disk 20 and the elastic force by the suspension 44 are balanced, the magnetic head 41 mounted on the slider 42 maintains a predetermined gap from the disk 20 that is rotating and records and reproduces data on and from the disk 20.
Next, referring to FIGS. 2 and 3, the structure of coupling the spindle motor 30, the magnetic disk 20, and the disk clamp 60 is described in detail. Typically, a shaft 32 of the spindle motor 30 is fixedly installed, and a hub 36 is rotatably installed at the shaft 32 by a bearing 34 at the outer circumference of the shaft 32. The disk 20 is inserted at the outer circumference of the hub 36. When a plurality of the disks 20 are installed, the ring type spacer 50 for maintaining a gap between the disks 20 is inserted around the outer circumference of the hub 36. The disk clamp 60 is coupled to the upper end portion of the hub 36 by the screws 70.
The edge portion of the conventional disk clamp 60 is bent as shown in FIG. 3 to press the upper surface of the disk 20. However, a structure to prevent a horizontal movement of the disk 20 is not provided. To insert the disk 20 around the outer circumference of the spindle motor 30, a relatively small gap G1 is present between the inner circumferential surface of the disk 20 and the outer circumferential surface of the spindle motor 30. Accordingly, when an impact is applied from the outside of the hard disk drive, in particular, from the side surface thereof, a horizontal movement of the disk 20, that is, a slip, is easily generated. When a slip of the disk 20 is generated, the magnetic head 41 cannot accurately read the data recorded on the surface of the disk 20.
Also, when a slip of the disk 20 is generated, the inner circumferential surface of the disk 20 collides against the outer circumferential surface of the spindle motor 30 so that an outside impact is delivered to the spindle motor 30 via the disk 20. Accordingly, the spindle motor 30, in particular, the bearing 34, can be damaged, causing disk fluttering and an increase in noise. In the meantime, the thickness of the disk 20 gradually increases to reduce the disk fluttering. As the disk 20 becomes thicker, the weight of the disk 20 increases, so that inertia increases when the disk 20 slips due to the outside impact. Accordingly, the force of an impact applied to the spindle motor 30 increases so that the spindle motor 30 and the bearing 34 are easily damaged.